Storing more data with stencils
Use compositing nodes in blender to for pixel image processing.  We  used a  


[Separate RGBA Node] and selected the R .. Red Channel.


Create an image sequence if that suits you.




In the image above we used a 3D scene with red and green object.  
In the compositing node view.  We view the red channel as intensity gray ...for red ball.  The green ball appears as black. I have clicked on a particular node to change the backgroud image of the nodes. 
In the lower left is a file input if that suits you for a image on your hard disk.  Otherwise you could map your images onto a plane.
I did not connect the file composite output ... so I could have many images in one screen shot. Connect the image you want to the final output.  
There are many good videos on a video site such as youtube as a random example. Search Blender Compositing Nodes.  Once you see a video these nodes will seem simple.  Please excuse my noodle soup.